La revue Journal of Vision met en ligne les résumés des contributions et posters présentés lors du congrès VSS 2015 qui s’est tenu St. Pete Beach (Floride) en mai 2015. Plusieurs contributions sont consacrées à l’autisme.

1. Freyberg J, Robertson CE, Baron-Cohen S. Reduced perceptual exclusivity during object and grating rivalry in autism. J Vis. 2015 Sep 1 ;15(13):11.

The dynamics of binocular rivalry may be a behavioral footprint of excitatory and inhibitory neural transmission in visual cortex. Given the presence of atypical visual features in Autism Spectrum Conditions (ASC), and the growing evidence in support of the idea of an imbalance in excitatory/inhibitory neural transmission in animal and genetic models of ASC, we hypothesized that binocular rivalry might prove a simple behavioral marker of such a transmission imbalance in the autistic brain. In support of this hypothesis, we previously reported a slower rate of rivalry in ASC, driven by longer transitional states between dominant percepts. We tested whether atypical dynamics of binocular rivalry in ASC are specific to certain stimulus features. 53 participants (26 with ASC, matched for age, sex, and IQ) participated in a binocular rivalry experiment in which the dynamics of rivalry were measured at two levels of stimulus complexity, low (grayscale gratings) and high (colored objects). Individuals with ASC experienced a slower rate of binocular rivalry, driven by longer transitional states between dominant percepts. These exaggerated transitional states were present at both low and high levels of stimulus complexity (gratings and objects), suggesting that atypical binocular dynamics in autism are robust with respect to stimulus choice. Interactions between stimulus properties and rivalry dynamics in autism indicate that achromatic grating stimuli produce stronger group differences. These results confirm the finding of atypical dynamics of binocular rivalry in ASC. These dynamics were present for stimuli of both low and high levels of visual complexity, suggesting a pervasive imbalance in competitive interactions throughout the visual system of individuals with ASC.

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2. Pell P, Mareschal I, Ewbank M, Baron-Cohen S, Calder A. Intact priors for gaze direction in autism spectrum conditions. J Vis. 2015 Sep 1 ;15(12):174.

Autism Spectrum Conditions (ASC) are characterized by a range of perceptual atypicalities, including abnormalities in gaze processing. Pellicano and Burr (2012) recently proposed that perceptual atypicalities might be a consequence of attenuated priors in ASC (i.e. reduced influence of prior knowledge on the perception of sensory information). Evidence from neurotypical populations indicates that under conditions of uncertainty (created by adding noise to the eyes of face stimuli), gaze is more likely to be perceived as direct (Mareschal et al., 2013), suggesting that humans have a prior expectation that other people’s gaze is directed toward them. Here we adopted the same paradigm to address two questions : 1) Is the influence of priors on gaze perception reduced as a function of autistic traits within a neurotypical population (Experiment 1) ? 2) Do individuals with diagnosis of ASC show evidence for reduced influence of gaze priors (Experiment 2) ? Each experiment began with a staircase procedure designed to tailor the noise contrast required for each participant to perform a left/right gaze discrimination at 80% correct. Participants were then required to judge the relative gaze directions of two faces when noise was added to the eyes of one face only. In Experiment 1, participants showed a significant bias towards perceiving uncertain gaze as direct, however this bias was not related to increasing autistic traits. In Experiment 2, individuals with ASC showed a robust direct gaze prior comparable to that of IQ matched controls. Given that noise-thresholds did not differ across groups, this finding is unlikely to reflect a combination of attenuated priors and increased sensory noise in ASC. These results pose a challenge to the hypoprior Bayesian model of ASC and suggest that if ASC is characterized by atypicalities in the use of prior information this is not reflected in their performance on a gaze task. Meeting abstract presented at VSS 2015.

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3. Xu B, Tanaka J. Investigating the face inversion effect in adults with Autism Spectrum Disorder using the fast periodic visual stimulation paradigm. J Vis. 2015 Sep 1 ;15(12):199.

Fast periodic visual stimulation (FPVS) is a powerful method for investigating the brain activity underlying human face processing. Previous studies have shown that FPVS provides a reliable index of the face inversion effect (FIE) (Liu-Shuang et al., 2013) and individual differences in face recognition ability (Xu et al., 2014). In the current study, the FPVS method was used to compare the discrimination of upright and inverted faces of 6 adults with Autism Spectrum Disorder (ASD) and 6 age-matched typically developed (TD) control participants. A repeated face stimulus (A) was presented at a frequency of 6Hz (F) for a 60-second block with a different oddball face (B, C, D) interspersed at every 5th cycle of presentation (F/5=1.2Hz) (i.e., AAAABAAAACAAAAD….). Faces within each 60-second block were presented either in their upright or inverted orientations. It is hypothesized that the 6Hz response reflects sensitivity to stimuli belonging to the generic face category whereas the 1.2Hz oddball response indicates sensitivity to a particular individuated face. The results showed that the repeated face stimuli produced an enhanced EEG signal at the fundamental 6Hz frequency and its harmonics (12Hz, 18Hz, etc.) with the largest activation found at medial-occipital electrode sites. Both the ASD and TD groups showed the FIE in which upright faces elicited a greater EEG amplitude than inverted faces. At the 1.2Hz frequency and its harmonics (2.4Hz, 3.6Hz, etc.) , participants in the TD group showed the FIE where a greater signal was generated by the upright oddball face than the inverted oddball face. In contrast, participants in the ASD group exhibited the same EEG response to the upright and inverted oddball face. The lack of the FIE to the individuated oddball face in the ASD group is consistent with the behavioral findings indicating that adults with ASD have difficulty discriminating individual faces. Meeting abstract presented at VSS 2015.

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4. Zachi E, Costa T, Barboni M, Ventura D. Correlation between chromatic sensitivity and higher order color vision functions in Asperger Syndrome but not in high functioning autism. J Vis. 2015 Sep 1 ;15(12):262.

The assumption that Asperger Syndrome (AS) and high functioning autism (HFA) are quantitative manifestations of the same disorder today remains somewhat controversial. The purpose of this study was to examine possible correlations between chromatic sensitivity and visual perception/memory for complex detailed colored stimuli in AS and HFA patients and controls. Ten patients with AS, 9 patients with HFA, and 12 controls were tested. The participants were 6 to 19 years old and had normal or above-average intelligence according to the Raven Matrices Test. University’s hospital psychiatrists made the diagnosis based on DSM-IV criteria. Short-term memory for colored stimuli was assessed with the Delayed Matching to Sample test (DMS) from the CANTAB battery. Color discrimination was measured using the Cambridge Colour Test (CCT). AS participants performed significantly better than the other groups in delayed perceptual matching (Kruskal-Wallis ANOVA, p&lt ; 0.05). Higher DMS total scores were significantly correlated with lower thresholds for protan (rS= -0.75), deutan (rS= -0.86), and tritan (rS= -0.81) axes and with narrow areas of the MacAdam ellipses (rS= -0.89) among patients with AS. Correlations between CCT values and DMS scores were not statistically significant for HFA participants and controls. Color vision losses (defined according to previous data from our Laboratory – Ventura et al., 2003) were found in 20% (2/10) of the patients with AS and in 44% (4/9) of the HFA group. Chromatic sensitivity seemed to influence the performance in a task that integrates color vision discrimination and complex processes including perception and memory in the AS group. The results corroborate the superior detailed information processing in Asperger Syndrome. This study supports a different profile of interaction between sensory and high-order cortical functions in AS and HFA. Meeting abstract presented at VSS 2015.

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5. Caplette L, Desroches P, Wicker B, Gosselin F. Autistic and neurotypical subjects extract spatial frequencies differently. J Vis. 2015 Sep 1 ;15(12):478.

When recognizing an object, low spatial frequencies (LSFs) are processed before higher spatial frequencies (HSFs), presumably through the faster magnocellular pathway. People suffering from autism spectrum disorders (ASD) however may not benefit from such a precedence of LSF information, several studies indicating a deficit in processing related to the magnocellular pathway (e.g., Sutherland & Crewther, 2010) and a preference toward HSFs rather than LSFs (e.g., Deruelle, Rondan, Gepner, & Tardif, 2004). Our study compared the time course of spatial frequency (SF) use in object recognition in neurotypical and ASD subjects. Forty-five neurotypical and 18 ASD subjects participated to the study. On each trial, a short video (333 ms) was presented to subjects. This video was created by selecting one of 86 object images, all equalized in SF content, and by sampling randomly its SFs across time. An object name immediately followed and subjects had to indicate if it matched the object (it did on half the trials) as quickly as possible without making too many errors. We then performed multiple linear regressions on SF x time sampling planes and accuracy. Most SFs between 0.08 and 4.42 cycles per degree (cpd) during almost all stimulus presentation (0 to 325 ms) led to more accurate responses for both groups (p&lt ; 0.05 ; Zmax=7.10). Interestingly, SFs between 3.75 and 4.33 cpd in the 58-100 ms time window (p&lt ; 0.05 ; Zmax=4.03) and SFs between 5.00 and 5.58 cpd in the 67-100 ms time window (p&lt ; 0.05 ; Zmax=3.99) led to more accurate responses for autistic subjects than for neurotypical subjects. These results indicate that while both groups use LSFs and intermediate SFs throughout object recognition, autistic subjects use more HSFs at a shorter latency. This suggests a different time course of SF extraction for autistic subjects. Meeting abstract presented at VSS 2015.

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6. Scherf KS, Legault J, Turney I, Elbich D, Minshew N, Behrmann M. Axial Diffusivity in the ILF and IFOF is Related to Autism Symptom Severity. J Vis. 2015 Sep 1 ;15(12):639.

Atypical neural activation within the face-processing network is widely reported in adults and adolescents with autism ; and, individual differences in symptom severity predict the magnitude of these atypical responses, particularly within posterior core regions of this network (Scherf et al., 2015). Also, recent evidence suggests that the inferior longitudinal fasciculus (ILF), a fiber tract that connects posterior core regions with more anterior extended regions, is developmentally disrupted in autism (Koldewyn et al., 2014). In typically developing children, the ILF shows changes in microstructural properties with age in terms of a reduction in mean and radial, but not axial, diffusivity (Scherf et al., 2014), which suggests ongoing myelination of this tract. In the current project, we investigated individual differences in the relation between symptom severity, age, and face recognition behavior and microstructural tract properties in 18 high-functioning adolescents (HFA) with autism. Participants were scanned using diffusion tensor imaging. Using Tract-Based Spatial Statistics, we created a mean white matter skeleton representing the centers of all tracts common to the group. From this, we computed axial, radial, and mean diffusivity (AD, RD, MD) maps and voxelwise regressions of age, scores from the Social Responsiveness Scale, and behavioral measures of face recognition on each diffusivity map. We found significant age-related changes in AD, but not RD or MD, in the right and left ILF and IFOF (inferior fronto-occiptical fasciculus), which was not present in a previous study with TD individuals, and may reflect increasing impairments in axonal transport with age. We also found a positive relation in these tracts between AD and SRS, which indicates that HFA adolescents with more severe symptoms may have more axonal damage in these tracts. These alterations in microstructural properties of key fiber tracts likely contribute to disruptions in face-processing behavior, and social behavior more broadly, in autism. Meeting abstract presented at VSS 2015.

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7. Chen YT, Chen HL, Tsou KS, Wong CC, Fang YT, Wu CT. Motor imagery vs. object-based visual imagery in adolescents with Autism Spectrum Disorder. J Vis. 2015 Sep 1 ;15(12):642.

Mental representation of actions is one of the essential components for social interaction and communication, and quite a few studies propose that social cognition deficits observed in ASD can be attributed to their aberrant action representation. Nevertheless, the hypothesis remains inconclusive primarily because most previous studies address this issue either through motor imitation that is contaminated by the requirement of overt motor replication, or through passive action observation that lacks active manipulation of action representation. In the current study, we aimed to investigate the characteristics of action representation in adolescents with ASD through motor imagery (MI) that requires both active manipulation and embodiments of action representation. We recruited 22 participants with ASD and 22 typically developing controls (TDC) to perform a hand-rotation and an object-rotation task. In the hand-rotation task (involves kinesthetic MI), participants were required to judge the laterality of a 3-D model image of a bare-hand (the transitive condition) or a hand-with-spoon (the intransitive condition) that rotates with different angles. In the object rotation task (involves object-based visual imagery), they were required to judge whether the drawer is on the right or on the left side of a desk that also rotates with different angles. Our results reveal that the two groups performed both tasks with compatible accuracy, but ASD is significantly slower than TDC only in the hand rotation task. Furthermore, both groups showed significant biomechanical constraint effects, indicating the usage of kinesthetic MI during the hand rotation task. Our findings suggest inefficient but not dysfunctional kinesthetic MI in individuals with ASD, an implication of preserved action representation. Unlike several previous findings in which ASD tends to use visual-spatial strategy to solve mental rotations of body parts, our data show that they can still spontaneously use kinesthetic MI when necessary. Meeting abstract presented at VSS 2015.

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8. Freyberg J, Robertson C, Baron-Cohen S. Atypical Binocular Rivalry Dynamics of Simple and Complex Stimuli in Autism. J Vis. 2015 Sep 1 ;15(12):643.

The dynamics of binocular rivalry are influenced by the balance of excitatory and inhibitory neural transmission in the brain. This balance is proposed to play an important role in the neural basis of Autism Spectrum Conditions (ASC). Binocular rivalry has therefore been proposed as a behavioural paradigm to test this theory. Two studies have compared rivalry dynamics between ASC and Control subjects, using stimuli of different levels of visual complexity. While both found results in the expected direction, only one found significant differences in rivalry dynamics between the two groups. First, we hoped to replicate our previous finding of a slower rate of rivalry with longer mixed percepts in ASC in a new, expanded sample of participants. Second, we tested whether this finding was selective for stimuli of a particular level of visual complexity (complex object or simple grating stimuli). 53 participants (26 with ASC, matched for age and IQ) completed twelve 40s trials of binocular rivalry (6 objects, 6 gratings) and 24 control trials. We analysed the rate of perceptual transitions and average percept durations. Repeated measures ANOVAs (with Stimulus Type as a between-subject and Diagnosis as a within-subject factor) revealed a lower rate of switches (F(1, 51) =4.3, p &lt ; 0.043) and longer mixed percepts (F(1, 51) =14.7, p &lt ; 0.001). These results remained significant when age and IQ were covaried. Group differences in mixed percept durations were confirmed with non-parametric comparisons to be significant in both stimulus conditions, while the difference in switch rate was significant only in the grating condition. We confirm a slower rate of rivalry in ASC, with and increased durations of mixed percepts, and find that this effect is present in simple grating stimuli. This result suggests that an increased excitatory/inhibitory ratio in autism may occur as early as primary visual cortex. Meeting abstract presented at VSS 2015.

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9. Guy J, Perreault A, Mottron L, Bertone A. A systematic examination of early perceptual influences on low-, mid and high-level visual abilities in Autism Spectrum Disorder. J Vis. 2015 Sep 1 ;15(12):644.

Studies investigating visual perception in Autism Spectrum Disorder (ASD) have identified atypical abilities mediated by low-, mid-, and high-levels of processing (Mottron 2006, Bertone et al 2010a). Much of this research, however, has focused on isolated levels of processing (i.e. low or high). It is therefore unknown if a functional relationship exists between levels of information processing, and moreover, if alterations in early levels of visual analysis influence mid- and high-level perception in ASD. The goal of this project was to systematically assess whether manipulating either (i) the type (luminance vs texture), or (ii) access to early, local information differentially affects performance on tasks targeting low-, mid- and high-level perceptual processes in ASD. Three separate studies examined the effects of manipulating physical stimulus properties on progressively complex visuo-spatial tasks : low-level perception was assessed using luminance- and texture-defined gratings over a range of low to high spatial frequencies ; mid-level perception was examined using luminance and texture-defined radial-frequency patterns manipulated to create « bumps » along their contours to optimize global (few bumps) and local (many bumps) processing ; high-level perception was assessed using a face-identification task where access to local and global cues was manipulated by presenting faces from different orientations and viewpoints. For the low-level task, results revealed an increased sensitivity of the ASD group for high-spatial frequency information in the luminance-defined condition. For the mid-level task, the ASD group performed worse than the control group for luminance-defined RFPs with few modulations, but similarly for those with many modulations. For the high-level task, individuals with ASD were significantly worse identifying faces in the view-change condition in which local cues were limited. Our findings indicate that visual abilities mediated by low-, mid- and high-level mechanisms in ASD are differentially affected by the nature and access to early visual information during task completion. Meeting abstract presented at VSS 2015.

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10. Cranwell M, Riby D, Le Couteur A, Pearce B, Hurlbert A. Dissociation of chromatic discrimination ability in developmental disorders : Autism Spectrum Disorder and Williams Syndrome. J Vis. 2015 Sep 1 ;15(12):645.

Atypical visual processing, particularly in dorsal stream functions, has been reported in both Autism Spectrum Disorder (ASD) and Williams Syndrome (WS), two developmental disorders which are typically said to have contrasting social profiles despite overlapping socio-communicative deficits. Here we aim to dissociate visual processing deficits between the two syndromes by examining ventral stream function, which underlies key aspects of socio-communicative ability such as face and object recognition ; we specifically examine colour perception. METHODS : Children (7-18 years) with ASD (N = 15) or WS (N = 26) and mental-age equivalent typically developing (TD) children (6-9 years) (N = 29) each completed two chromatic discrimination tasks : (1) the Farnsworth-Munsell 100-Hue Test (FM100), a manual cap-sorting task requiring the ordering of hues at equal lightness and saturation to form a smooth chromatic gradient, and (2) a computer-based threshold discrimination test, which assessed discrimination along cone-opponent (« red-green », « blue-yellow ») and luminance cardinal axes using a controlled staircase procedure. Participants were required only to report, on each trial, the direction of a single arrow briefly shown against a grey background. RESULTS : In FM100 performance, there was a significant difference between the WS and TD groups, but not between ASD and TD groups. Yet, in each group, performance was significantly related to non-verbal IQ, and this relationship was stronger in the ASD and WS groups. For the threshold task, a significant group by colour-axis interaction was found between TD and ASD, driven by significantly poorer « blue-yellow » discrimination in ASD. Between the WS and TD groups there were no significant differences in performance. Crucially, there were no significant correlations between threshold task performance and non-verbal ability. CONCLUSION : Chromatic discrimination is reduced in ASD but not in WS, relative to TD, but this dissociation is not revealed by a task which confounds visual discrimination ability with general intellectual ability. Meeting abstract presented at VSS 2015.

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11. Manning C, Morgan M, Allen C, Pellicano E. Do children with autism show reduced susceptibility to the Ebbinghaus illusion ?. J Vis. 2015 Sep 1 ;15(12):646.

Reports of reduced susceptibility to visual illusions in autistic individuals have generally been attributed to differences at the level of the percept. However, group differences could instead reflect differences in higher-level decision-making strategies. Here, we measured the perceptual biases of 28 children with autism aged 6 to 14 years and 32 age- and ability-matched typical children using a 2-alternative-forced-choice method with a roving pedestal designed to minimise response and decision biases (Morgan, Melmoth & Solomon, 2013, Visual Neuroscience 30:197-206). Children were presented with a reference stimulus and two comparison stimuli (see Figure 1), and asked to identify which comparison stimulus had a central circle most similar in size to that of the reference stimulus. One comparison stimulus was a pedestal, which had a central circle either 5% larger or 5% smaller than the reference stimulus. The other comparison stimulus had a central circle that was an increment larger than the pedestal. The pedestal size (+5%, -5%) was randomly interleaved throughout the task, so that children did not know which of the two comparison stimuli was the pedestal on a given trial. Children completed this task in two context conditions : with small surrounding circles on the reference and large surrounding circles on the comparison stimuli (S-L), and vice versa (L-S ; see Figure 1). The data were fit with a cumulative normal psychometric function using the maximum likelihood estimate technique, modelling the effect of context condition as an equivalent pedestal with no effect on internal noise. Children with autism had typical levels of internal noise and exhibited a similar degree of perceptual bias to that of typically developing children. Our results are inconsistent with theories proposing reduced contextual integration in autism and suggest that previous reports of reduced susceptibility to illusions arise from differences in response or decisional criteria, not perceptual differences. Meeting abstract presented at VSS 2015.

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12. Peterson J, Reed S, Kenny R, Dassonville P. A Two-Factor Structure within the Systemizing Trait of Autism Differentially Predicts Susceptibility to Lateral and Collinear Flanker Effects. J Vis. 2015 Sep 1 ;15(12):647.

Previous work has demonstrated that two separate components of the systemizing trait of autism differentially predict susceptibility to the mechanisms that drive the Rod-and-Frame illusion, with an Analytical Tendencies factor associated with reduced reliance on global cues, and an Insistence on Sameness factor associated with increased susceptibility to local orientation contrast effects (Reed & Dassonville, VSS 2012). However, it is unclear whether these associations reflect atypical contextual modulation only at higher levels of processing, or whether low-level visual processes (i.e., in primary visual cortex) may also be affected. To examine this, we compared scores on the Systemizing Quotient-Revised (Wheelwright et al., 2006) in the general population to individual differences in the contextual modulation of perceived orientation induced by lateral and collinear flankers, presented at the estimated size of V1 receptive fields. When an observer judges the orientation of a central line in the presence of lateral flankers, the perceived orientation of the line is biased in the direction opposite the tilt of the flankers (a repulsive effect), while the same judgments made in the presence of collinear flankers bias the perceived orientation of the line in the same direction as the flankers (an attractive effect). We found that higher scores on the Analytical Tendencies factor of the SQ-R were associated with reduced contextual effects of collinear flankers, but were unrelated to contextual interactions induced by lateral flankers. Conversely, higher scores on the Insistence on Sameness factor were associated with increased contextual effects of lateral flankers, but were unrelated to contextual effects induced by collinear flankers. These findings suggest that distinct systemizing tendencies differentially predict low-level contextual interactions that are thought to occur in primary visual cortex, and provide insight to the relationship between the functional structure of V1 and the behavioral tendencies associated with autism. Meeting abstract presented at VSS 2015.

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13. Wang C, Shimojo E, Shimojo S. Don’t look at the eyes : Live interaction reveals strong eye avoidance behavior in autism. J Vis. 2015 Sep 1 ;15(12):648.

Atypical social gaze is commonly observed in individuals with autism (ASD) in real-world and clinical settings. Laboratory tasks using social stimuli have shown reduced gaze to face and eyes and reduced social orienting in high-functioning adults compared to neurotypical (NT) controls, although differences were often marginal, perhaps due to static stimuli or non-interactive tasks. In this study, we investigated gaze during live, naturalistic interactions between pairs of participants conversing freely about their interests, while gaze and video were recorded for both. Results from 8 NT and 7 ASD participants revealed distinct gaze patterns, distinguishing the groups. All NT participants displayed a consistent pattern of high gaze frequency and duration (mean=54%) to the eyes and low gaze to the mouth (mean=1%). ASD participants showed significantly lower gaze frequency (mean=10%, p&lt ; 0.00000001) and duration (mean=7%, p&lt ; 0.000001) to the eyes, with higher frequency (mean=33%, p&lt ; 0.02) and duration (mean=39%, p&lt ; 0.02) to the mouth, and no difference for the face (NT mean=77%, ASD mean=72%, n.s.). Only NTs showed a significant preference for the left eye in frequency (p&lt ; 0.05) and duration (p&lt ; 0.04). Mouth gaze split ASD participants into subgroups of high (N=4) or low (N=3) frequency, but long mouth fixations characterized ASD overall (640 ms) and distinguished (p&lt ; 0.01) from short fixations (210 ms) in NT. Together, these results show that live, interactive experiments can detect striking differences in social gaze between NT and ASD groups. The NT pattern is defined by high eye contact with occasional, passing glances at the mouth, while ASD shows a strong, spontaneous tendency to avoid the eyes and prolonged fixations to the mouth. Diversion of gaze to the mouth or other face regions (e.g. nose, cheeks, forehead) suggests a compensatory mechanism for eye avoidance that allows face gaze without direct eye-to-eye contact in ASD. Meeting abstract presented at VSS 2015.

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14. Yi L, Quinn P, Feng C, Lee K. Do Individuals With Autism Spectrum Disorder Process Own- and Other-Race Faces Differently ?. J Vis. 2015 Sep 1 ;15(12):649.

A growing literature has demonstrated a robust other-race effect (ORE) in typically developing (TD) individuals. That is, they recognize and discriminate own-race faces more accurately than faces from other racial groups. Considering that there is inconsistency in the evidence regarding the existence of a behavioral ORE in autism spectrum disorder (ASD ; Chien et al., 2014 ; Wilson, 2011), we investigated face scanning patterns using eye tracking, to provide a different measure of processing race information from faces. It has been shown that Chinese observers tend to focus on the central region (i.e., the nose) of Chinese faces and the eye region of Caucasian faces (Fu et al., 2012 ; Liu et al., 2011). The present study examined whether individuals with ASD would, like typical individuals, show differential patterns of visual scanning when viewing own- and other-race faces. The study included Chinese adolescents and young adults with ASD, age-matched TD individuals, and IQ-matched individuals with intellectual disability (ID). Participants completed a face recognition task with both Chinese and Caucasian faces, while their eye movements were tracked. Results indicated that (a) in terms of recognition, the ASD and ID groups, although not the TD group (due to a ceiling effect), displayed superior recognition of own-race relative to other-race faces ; (b) different from TD and ID groups, individuals with ASD showed atypical face processing patterns regardless of face race ; (c) similar to TD and ID individuals, individuals with ASD fixated on the eyes of other-race faces longer than those of own-race faces, whereas they looked at the nose and mouth of own-race faces longer than those of other-race faces. The results suggest that similar to TD individuals, individuals with ASD are sensitive to face race information : their visual scanning and recognition of faces are both influenced by asymmetrical experience with different types of faces. Meeting abstract presented at VSS 2015.

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15. Sun S, Stevenson R, Hazlett N, Barense M, Cant J, Ferber S. Individual differences in autistic traits predict visual binding abilities. J Vis. 2015 Sep 1 ;15(12):846.

A core symptom of autism spectrum disorder (ASD) is a deficit in binding sensory inputs into a unified representation. Past research suggests that these impairments extend from lower-level perceptual grouping to higher-level holistic face perception. Given that visuo-spatial attention plays a critical role in binding, we hypothesized that normally-distributed autistic traits in the healthy population would predict the degree to which attentional scope could be modified to influence holistic face perception. We directed participants to adopt either a global or local attentional scope using a Navon task. Participants viewed pairs of Navon letters (big letters composed of small letters) and made same/different judgments based on attention to the big (global scope) or small (local scope) letter. The effects of this manipulation were measured on the composite face task, a well-established measure of holistic face perception. Autistic traits and sensory processing styles were measured using the Autism Quotient (AQ) and Sensory Profile (SP), respectively. In the Navon task, we observed a global interference effect, that is, greater susceptibility to interference from global information, relative to local. Furthermore, individuals with higher SP scores showed weaker global interference effects. ASD has been associated with both abnormal sensory processing styles, as well as weaker global interference effects. Consistent with this idea, we found an interaction in that SP was more strongly associated with global interference in individuals with higher AQ scores. In the composite face task, we found that the attention-to-detail subscale of the AQ predicted differences in susceptibility to the composite face illusion between global and local conditions. Specifically, individuals high in autistic traits were less capable of adopting a global attentional setting, which led to weaker holistic face perception. These results shed light on how autistic traits and sensory processing styles converge to influence visual binding abilities. Meeting abstract presented at VSS 2015.

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16. Corbett J, Melcher D. Evidence for global perceptual averaging in individuals with Autism Spectrum Disorder. J Vis. 2015 Sep 1 ;15(12):847.

Studies of visual perception in individuals with Autism Spectrum Disorder (ASD) report enhanced local processing, and either impaired or suppressed global processing. In contrast, we report evidence of global size averaging despite poor accuracy at recalling sizes of individual objects, as well as a persistent contextual influence of adaptation to mean size on the perceived size of single objects across groups of ASD and control observers. In Experiment 1, participants viewed a set of heterogeneously sized circles followed by two test circles and judged which test circle represented the mean size (mean task), or was a member (member task) of the set. Despite their noted hypersensitivity to local detail, the ASD group showed the same patterns of high accuracy in the mean task and chance accuracy in the member task as the control group, in-line with Ariely’s (2001) proposal that observers can extract average properties of sets without retaining information about individual items. In Experiment 2, participants adapted to two patches of heterogeneously sized dots with large and small mean sizes, then judged which of two subsequently presented test dots was larger. Contrary to the notion that individuals with ASD are better at suppressing global context, both groups perceived the sizes of the physically identical test dots as an inverse function of the preceding adapting patches. This negative aftereffect of mean size adaptation across observers supports the proposal that mean size is encoded as a fundamental visual attribute (Corbett, et al., 2012). Taken together, results suggest that individuals with ASD show normal sensitivity to such contextual regularities in the surrounding environment. Our findings not only provide further evidence for the fundamental nature of perceptual averaging in vision, but also raise questions for theories that predict superior local visual processing and impaired or suppressed global visual processing in individuals with ASD. Meeting abstract presented at VSS 2015.

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17. Karaminis T, Neil L, Manning C, Turi M, Fiorentini C, Burr D, Pellicano L. Ensemble perception of emotions in children with autism. J Vis. 2015 Sep 1 ;15(12):916.

Ensemble perception, the ability to rapidly and automatically assess the summary or ‘gist’ of large amounts of information presented in visual scenes, is available early in typical development (Sweeny et al., in press). Ensemble perception might be compromised in children with autism, who have been proposed to present limitations in their abilities to maintain and/or use summary statistics representations for the recent history of sensory input, which might be responsible for their unique perceptual experience (Pellicano & Burr, 2012). Here we examined ensemble perception of emotions in 29 children with autism, aged between 6 and 14 years, 30 age- and ability-matched typical children, and 12 typical adults. Participants received three child-friendly tasks : a) an average (ensemble perception) emotion discrimination task, assessing their ability to judge the average happiness of a set of ‘morphs’ ; b) a non-average happiness discrimination task, evaluating baseline emotion discrimination ; and c) a face identification task, estimating children’s ability to identify morphs that had been previously presented to them. We also monitored participants’ eye movements while they performed the three tasks using a Tobii X2-30 eye tracker (30 Hz). All three groups presented better precision in the non-average than in the average emotion discrimination task, while children’s precision and accuracy in the three tasks were worse than those of adults- suggestive of a gradual and parallel maturation of emotion discrimination, ensemble perception, and face-processing abilities. Unexpectedly, children with autism were indistinguishable from typical children in their precision and accuracy across the three tasks. On eye-movement variables, the three groups did not differ in terms of the average number of fixations and the number of morphs sampled per trial. Contrary Pellicano and Burr (2012), these findings suggest that autistic children’s abilities for ensemble perception of emotions are largely similar to those of typical children. Meeting abstract presented at VSS 2015.

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18. Robertson C, Hermann K, Ratai EM, Kanwisher N. GABA Measured in Visual Cortex using MRS Predicts Atypical Dynamics of Binocular Rivalry Associated with Autism. J Vis. 2015 Sep 1 ;15(12):917.

INTRO : The primary agent of inhibitory neurotransmission in visual cortex, GABA, has been linked to autism etiology in animal, genetic, and post-mortem studies. Specifically, GABA is thought to be down-regulated in the autistic brain, producing an overabundance of excitatory neurotransmission. Yet, perturbations in GABAergic signaling have never been experimentally associated with behavioral symptoms in people with autism. We recently demonstrated a striking autistic deficit in binocular rivalry (Robertson et al., 2013), a visual behavior that is governed by Excitatory/Inhibitory dynamics in the brain. Here, we tested whether the dynamics of binocular rivalry in typical adults are correlated with levels of excitatory (glutamate) and inhibitory (GABA) neurotransmitters measured in vivo. METHODS : We measured binocular rivalry dynamics in 18 control participants, as well as the concentration of excitatory (glutamate) and inhibitory (GABA) neurotransmitters in the primary visual (test) and motor (control) areas of each individual’s brain using Magnetic Resonance Spectroscopy (MRS). RESULTS : GABA in V1 strongly predicted the dynamics of binocular rivalry in control individuals (Proportion of mixed percepts : rho = -0.61, p &lt ; 0.008) – where less GABA predicted slower binocular rivalry dynamics with longer mixed percepts, corresponding to the atypical dynamics we previously observed in ASD. This relationship was observed for rivalry using both simple (gratings) and complex stimuli (objects) (both r &lt ; -0.6, p &lt ; 0.009). Further, these results were specific to visual cortex : while GABA concentration in M1 predicted performance on a Go/No-Go motor task (rho = 0.67, p &lt ; 0.002), it did not predict rivalry dynamics (rho = -0.35,p &gt ; 0.19). CONCLUSIONS : Here, we demonstrate that a robust behavioral alteration in individuals with ASD strongly predicts GABA concentration measured in controls. This research may lead to the first experimental demonstration of a link between a robust autistic symptom and a prominent theory of autistic neural circuitry. Meeting abstract presented at VSS 2015.

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19. Whyte E, Elbich D, Behrmann M, Minshew N, Scherf KS. Altered functional connectivity in the core and extended face-processing network in adolescents with autism. J Vis. 2015 Sep 1 ;15(12):1209.

Atypicalities in the development of regions within the core and extended face-processing network have been implicated in the development of social symptoms for individuals with autism (Schultz, 2005 ; Scherf et al., 2014). As a result, the functional organization among these regions may also be impacted. Uddin, Supekar, & Menon (2013) proposed a developmental model, suggesting that adolescence may be a time of functional under-connectivity in neural networks of individuals with autism. To investigate whether the face-processing network exhibits such functional under-connectivity in autism, the current study examined functional connectivity within the face processing networks of 14 adolescents with high functioning autism (HFA) and 14 typically developing (TD) adolescents (13 to 18 years). The fMRI task consisted of a 1-back memory task while viewing multiple visual categories including : human faces, animal faces, and common objects. Regions in the face-processing network were defined at the group level separately for TDs and HFAs, and then fit to each participant’s individual activation. For connectivity, the best-fit model for the 12 regions was assessed for each group separately using unified structural equation modeling. We computed graph theory metrics based on the connection weights for each individual participant. The HFA adolescents had significantly higher clustering coefficients and global efficiency (p &lt ; .05), denoting more direct connections between regions. Following this, there was also a trend for the HFA group to have a greater number of edges or connections between regions. These results suggest that task-related functional connectivity between individual regions in the face-processing network of HFA adolescents is largely over-connected compared to TD adolescents. These results converge with our additional findings that TD adults with weaker face recognition abilities also have over-connected networks compared to those with stronger abilities. Together, these findings suggest that over-connected, redundant networks may interfere with proficient face-recognition behavior. Meeting abstract presented at VSS 2015.

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20. Ewbank M, Pell P, Powell T, von Em Hagen E, Baron-Cohen S, Calder A. Reduced repetition suppression to faces in the fusiform face area of adults with autism spectrum conditions. J Vis. 2015 Sep 1 ;15(12):1210.

In neuroimaging studies, repetitions of the same stimulus typically result in a reduction in neural activity, known as repetition suppression (RS). Repeated presentation of the same face is associated with RS in core regions of the face processing network, including the fusiform face area (FFA). At a behavioural level, repeated viewing of the same stimulus causes a change in perceptual sensitivity, known as a visual aftereffect. Evidence indicates that visual aftereffects for faces are attenuated in children and adolescents with autism spectrum conditions (ASC), leading to the proposal that atypical adaptive coding in face processing networks may underlie difficulties in face learning and memory found in ASC. However, whether individuals with ASC show reduced RS to faces remains to be addressed. Here, we used functional MRI to investigate RS to faces and non-faces (simple geometric shapes) in adults with a clinical diagnosis of ASC. We measured activity in face- and object-selective regions of occipitotemporal cortex while participants viewed blocks of images comprising repetitions of the same face/shape or images of different faces/shapes. Participants also completed standardized behavioural tests of face and car memory. Relative to age and IQ matched controls, individuals with ASC showed diminished RS to faces in right FFA. By contrast, RS to shapes in object-selective regions did not differ between groups. This finding could not be explained by differences in gaze fixations or face-selectivity in FFA. In addition, behavioural data revealed that individuals with ASC showed a significant impairment in face memory (compared to controls) but not car memory. These findings suggest reduced RS in FFA as a possible neural mechanism underlying attenuated facial aftereffects found in ASC, and suggest that differences in the adaptive properties of the face-processing network may underlie difficulties in face learning and memory associated with this condition. Meeting abstract presented at VSS 2015.

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21. Cook R, Shah P, Gaule A, Brewer R, Bird G. Autism and Developmental Prosopagnosia : A Cross-Disorder Study. J Vis. 2015 Sep 1 ;15(12):1211.

It has been suggested that developmental prosopagnosia (DP) and autism spectrum disorder (ASD) are co-occurring conditions ; i.e., that the incidence of DP is greater in ASD than in the general population, and vice versa. Consistent with this suggestion, several case studies have described individuals with ASD who also exhibit severe face recognition difficulties. These reports document a number of anecdotes widely regarded as classic hallmarks of DP, including the use of hairstyle, voice and clothing cues for identity recognition. Despite the hypothesized relationship between the two conditions, virtually nothing is known about the effects of co-occurring DP on the perceptual abilities of individuals with ASD, or the effects of co-occurring ASD in DP. The present study sought a better understanding of this co-occurrence, and the respective influence of ASD and DP on face and object recognition. A novel three group design was employed, allowing direct comparison of 18 observers with ASD, 18 with DP and 18 typically developing controls. All participants completed measures of prosopagnosic and autistic traits, and completed objective measures of face and object recognition ability. Consistent with the co-occurrence hypothesis, we found that i) individuals with ASD reported more prosopagnosic traits, and ii) individuals with DP reported more autistic traits, than controls. A subset of the ASD group reached the threshold for prosopagnosia and a subset of the DP group reached cut-off for clinically significant levels of autistic traits. As expected, prosopagnosic traits correlated closely with face recognition ability. Interestingly however, autistic traits were not predictive of face recognition ability once prosopagnosic traits were accounted for, but were associated with wider object recognition ability. These results have important implications for future research addressing visual perception in ASD and DP. A better appreciation of this co-occurrence may help to understand the heterogeneity seen in these conditions. Meeting abstract presented at VSS 2015.

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22. Rutherford MD, Walsh J, Creighton S. Emotion perception or social cognitive complexity : What drives face processing deficits in autism spectrum disorder ?. J Vis. 2015 Sep 1 ;15(12):1223.

Faces convey information about sex, identity, age, ethnic group, and internal emotional state, and typical individuals are expert at encoding and interpreting facial information. Individuals with ASD have difficulties with social perception and cognition, and there has been a great deal of scientific focus on the ability of those individuals with ASD’s to processing facial information. Still, there is not a clear consensus as to what the core deficits in face processing are characteristic of ASD. The current study examined whether the anomalies in face processing seen in adults with ASD are better explained as a deficit in processing emotions, or a deficit in processing the complexity of social stimuli. Participants completed a battery of four face processing tasks : identity discrimination, basic expression perception, complex emotion expression, and trustworthiness perception. The tasks either did or did not involve processing facial expressions, and also varied in the level of social cognitive complexity. If the deficits in face processing in ASD are driven by a core deficit in processing emotional expression information, participants with ASD would perform worse on the basic and complex expression perception tasks. In contrast, if their deficit is related to processing socially complex facial information, they would show poorer performance on the complex expression and trustworthiness perception tasks. Results revealed that ASD participants showed worse performance on basic expression recognition task (t(44) = 3.06, p = .004) and the complex expression recognition task t(44) = 4.26, p &lt ; .001 compared to typical participants. In contrast, there were no significant group differences in performance on the identification task (t(44) = 1.33, p = .19) or the trustworthy perception task t(44) = .93, p = .36. These results support an emotion processing rather than a social complexity explanation for face processing deficits in ASD. Meeting abstract presented at VSS 2015.

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23. Mevorach C, Muller Spaniol M, Shalev L. Enhanced pro-active distractor filtering in adults with high autistic traits. J Vis. 2015 Sep 1 ;15(12):1338.

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition involving a variety of impairments including impaired social interaction and restricted and repetitive interests and activities. While ASD is heterogeneous in its presentation, a number of studies have attempted to highlight core impairment in attention in ASD. However, such studies have reported somewhat conflicting findings. For instance, it has been suggested that ASD is often accompanied by impaired attention disengagement but also improved ability to ignore irrelevant distractors. In two experiments we investigated performance of typically developed adults with or without high autistic traits (AQ, Baron-Cohen et al., 2001) in tasks highlighting distractor filtering in a pro-active manner. In the first experiment participants had to select the global or local aspect of a hierarchical letter under conditions where the target or the distractor level is more salient ; in the second, we measured performance threshold when participants identify a face in a morphed face continuum superimposed on an irrelevant distractor. Across the two experiments we found that adults with high AQ were better at ignoring distractors than adults with low AQ. In the global/local task the high AQ group exhibited smaller congruency effects and in the morphed faces task they exhibited increased thresholds. Critically however, there were no overall differences in either the global and local conditions or in the morphed face categorization functions across the groups, precluding differences in low-level perceptual processes. The data support the notion that autistic tendencies are associated with increased attention filtering. We hypothesize that this enhanced filtering represents a bias towards pro-active control of attention (when the task set should be invoked in advance of stimuli presentation). This bias may in turn compromise re-active control, which might be called upon in situations where attention must be disengaged and reoriented. Meeting abstract presented at VSS 2015.

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